EduNinjaWhy is the boiling point of ammonia, , higher than the boiling point of phosphine, ?
Ammonia molecules are polar; phosphine molecules are not.
Ammonia molecules have significant hydrogen bonding; phosphine molecules do not.
N-H covalent bonds are stronger than P-H covalent bonds.
There is one lone pair in each ammonia molecule but no lone pair in each phosphine molecule.
The elements phosphorus, sulfur and chlorine are in Period 3 of the Periodic Table.
Table 1.1 shows some properties of the elements P to Cl .
The first ionisation energy of S is not shown.
Table 1.1
shows similar chemical properties to .
has a melting point of and a boiling point of .
reacts vigorously with water, forming misty fumes and an acidic solution.
Explain how the information in (d) suggests the structure and bonding of is simple covalent.
The melting points of some solids are shown in Table 1.1.
Table 1.1
Name the strongest intermolecular force that exists between molecules.
Draw a diagram to show the formation of the strongest intermolecular force between two molecules of .
Include any relevant lone pairs of electrons and dipoles.
The melting points of ice and ammonia are shown in Table 1.2.
Table 1.2
Suggest two reasons for the difference in the melting points of ice and ammonia.
The Pauling electronegativity values of elements can be used to predict the chemical properties of compounds.
Use the information in Table 1.1 to answer the following questions.
Table 1.1
Complete Table 1.2 by placing a tick to show which of the compounds have molecules with an overall dipole moment.
Table 1.2
Hydrogen iodide, HI, is a colourless gas at room temperature.
Explain why HI has a higher boiling point than HCl and HBr .
The bar chart shows the boiling points of HCl, HBr and HI . The boiling point of HF is not shown.
Hydrogen bonds form between HF molecules.
Draw a bar on the bar chart to predict the boiling point of HF .
Explain your answer.
The elements sodium to sulfur react with chlorine. The melting points of some of the chlorides formed are shown.
Explain why the melting point of is higher than that of .
The boiling points of some molecules with equal numbers of electrons are given.
Explain why the boiling points of fluorine and argon are so similar.
Explain why the boiling point of hydrogen chloride is higher than that of fluorine.
Explain why methanol has the highest boiling point of all these molecules.
Neon is a noble gas.
Neon and argon can both be obtained by fractional distillation of liquid air as they have different boiling points.
Neon has a boiling point of 27.3 K . The boiling point of argon is 87.4 K .
Name the force that has to be overcome in order to boil neon or argon and explain what causes it.
Explain why argon has a higher boiling point than neon.
Group VII is the only group in the Periodic Table containing elements in all three states of matter at room conditions.
State and explain, in terms of intermolecular forces, the trend in the boiling points of the elements down Group VII.
Ammonia, , and methane, , are the hydrides of elements which are next to one another in the Periodic Table.
Ammonia is polar whereas methane is non-polar. The physical properties of the two compounds are different.
Explain, using ammonia as the example, the meaning of the term bond polarity.
Explain why the ammonia molecule is polar.
State one physical property of ammonia which is caused by its polarity.